Four environmental groups filed court papers Thursday to take part in North Carolina’s enforcement case against Duke Energy over the Dan River ash spill.

The groups claimed that state officials have ignored numerous discharges from the retired Dan River power plant’s two ash ponds. They say the leaks continue well after the Feb. 2 spill.

A broken stormwater pipe under the main ash pond dumped up to 39,000 tons of ash into the Dan.

State environmental officials cited Duke for illegal discharges and not having a stormwater permit after the spill but have not levied fines. Duke said last week that it will permanently close the plant’s ash ponds. Bruce Henderson